Sansa hears him before she sees him. It's been a long, long time since she's heard his voice and after asking and asking if he'd made it out of King's Landing after she fled, now she has her confirmation. In at least one place, Tyrion Lannister is alive and healthy enough to ask someone where he is.

Her heart beats queerly for a moment before she finds herself and turns to find him because she has quite a few things to say to her first husband, chief among them how thankful she is that he'd been kind to her. Sansa hasn't seen much kindness of late.

"Lord Tyrion! Tyrion, it's Sansa." Oh, of course he knows it's her. He's not stupid and he's not blind. Why did she say that?